Universal method and apparatus for conversion of volatile compounds

ABSTRACT

A method or process of treating a contaminated fluid ( 10 ) having at least one contaminant having a property selected from the group consisting of being volatile, hazardous, tacky and a combination thereof is provided. The method comprises contacting the contaminated fluid with an effective amount of an agent ( 12 ) selected from oxidizing agents, free radical producing agents and a combination thereof for an effective amount of time to convert a substantial amount of the at least one contaminant to at least one corresponding modified contaminant having a property selected from the group consisting of being non-volatile, less volatile than the converted contaminant non-hazardous, less hazardous than the converted contaminant, non-tacky and a combination thereof; and generating a treated fluid ( 14 ) having a level of the at least one contaminant and of the at least one corresponding modified contaminant to allow the treated fluid to at least meet requirements for release, reuse or further treatment.

This application claims the benefit of Provisional Application No.60/194,445, filed Apr. 4, 2000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and apparatus to control andlimit the emission and discharge of volatile and malodorouscontaminants, such as those identified as VCs, VOCs, VICs, NO_(x),SO_(x), MCs, HAPs and other regulated contaminants,

2. Description of Prior Art

Numerous compounds used in various industries are recognized asenvironmental health hazards and pollutants. Regulatory control in theUnited States and other countries has led to constantly increasingrestrictions on discharge of such contaminants. While various separationand destruction methods have been utilized to remove contaminants fromthose waste products requiring disposal, many of the methods utilizedare prohibitively expensive, especially for small facilities withlimited resources. Low concentration high volume flows carry largeenergy and power penalties when treated with conventional technologies,and contribute to green house gas problems. Many small emission sourcesremain uncontrolled due to the prohibitive cost of installing andoperating conventional systems.

Air contaminants are produced by many industries in many forms. Someindustries produce Volatile Contaminants (VCs), Hazardous Air Pollutants(HAPs), or Malodorous Compounds (MCs) as part of a waste gas stream.Many industrial processes are dependent on evaporative processes thatcontaminate fluid process flows with VCs, HAPs, or MCs. In otherindustries, the contaminants are absorbed into a liquid solvent makingthe solvent unfit for further use. Contaminants may be entrained as aresult of a scrubber process, or as a result of a processing of othermaterials. These contaminants can be present in liquid or gas streamsdepending on the industry or the source. VOCs are also found incontaminated ground water and soil. Such occurrences lead to the needfor remediation.

Regulations on air quality affect a wide variety of industries. TheFederal Clean Air Act (FCAA) applies to air emissions establishing airquality standards, emission standards for hazardous air pollutants, newsource performance standards, acid deposition limits, and particulatedischarge emission limits. The Federal Clean Water Act (FCWA) addressescontrol of pollutants to the environment through liquid discharge.Hydrocarbon and petrochemical industries are affected by theserestrictions. Industries that burn fossil fuels, such as for powergeneration, are also affected by these emission limits. From paint shopsand bakeries to dry cleaners, there is a need for a method and apparatusto dispose or destroy these contaminants. Such treatment methods mustoperate in an efficient and cost-effective manner without producing newpollutants or depleting valuable resources.

One of the methods currently available for handling contaminants isequilibrium distillation. To achieve high purity products requires anincreased number of stages, increased energy input to increase refluxand/or vessels designed for non-atmospheric pressure operation. Whenmultiple solvents are combined prior to being regenerated, closerelative volatilities and azeotropes can make equilibrium separationparticularly difficult. While solvent can be recovered by this method,some solvent is typically lost to the contaminant by-product.Furthermore, while the major portion of contaminants may be concentratedin one by-product, the contaminant remains essentially in the same formand thus requires further treatment to complete disposal or destructionof the contaminant. These methods simply concentrate the contaminantsthat must then go to disposal or further treatment and separation steps.

Numerous filtration methods have also been utilized includingultrafiltration techniques. Various entrained solids or filter aids havebeen tried including activated carbons, titanium oxides, aluminas, ironoxides and silicas. Filter media with contaminants then face the samedisposal challenge since the contaminants are trapped within the media.

Destruction techniques involve subjecting the contaminants to extremethermal conditions such that the contaminants are broken down intosimpler components, such as CO₂, H₂O and even elemental components.Destruction techniques typically involve large additional energy inputsand substantial space requirements. This combination is ofteneconomically inefficient for significant volumes of throughput andwastes limited hydrocarbon resources. Available destruction techniquesinclude thermal oxidation, incineration, and catalyticincineration/oxidation. Incineration, i.e., oxidative destruction, seeksto oxidize the contaminants to produce primarily CO₂ and H₂O. Notably,the release of CO₂ is also becoming regulated as a greenhouse gas andmay soon have limits placed on its discharge. Particulate matter tendsto negatively affect some incineration processes as well as releaseparticulate matter that contributes to ground level ozone (smog)formation.

Thermal oxidation works on the principle of an afterburner. The heatenergy required to reach combustion temperatures is typically suppliedby the oxidation of the contaminants in the more efficient systems.However, when only low concentrations of the contaminant are available,large amounts of energy must be added to the effluent stream to reachthe required temperature to destroy the contaminants. In addition tocreating thermal pollution and green house gases, it makes thermaloxidation inefficient and cost prohibitive.

Disposal of liquid and/or solid wastes containing these contaminants isalso costly. It is desirable to treat hazardous contaminants usingchemical reactions where the contaminant is converted to a non-hazardousor sometimes even useful reusable material. One specific example of thisincludes the decomposition of volatile organic halogenated compounds(VOHC) by passing the compound through a porous silica gel bed andexposing the gel to ultraviolet light and/or ozone. Some of thedifficulties involved with this technology include the expense anddifficulties of maintaining and regenerating the silica gel bed,particularly as the bed tends to foul when particulate matter isintroduced in the stream to be treated. Another specific example of suchreaction includes the destruction of perchlorethylene (PERC) in the drycleaning industry by “burning up” the PERC using ozone. Both of theabove methods require substantial amounts of ozone to achieve theirgoals. Furthermore, the use of ozone or other oxidizing agents forcomplete destruction requires the use of an amount stoichiometricallydetermined to completely convert the amount of contaminants available toH₂O, CO₂, and HCl. A very large amount of excess (i.e., beyondstoichiometric requirements) ozone or oxidizing agent is also consumedby other oxidizable materials present in the matrix. Even more ozone iscatalytically converted back to O₂ by reaction with itself, or wasted asan offgas to a destruction device that converts O₃ back to O₂. Ozone isundesirable as an off-gas. Additional steps become necessary to removeexcess ozone. It is recognized that continued exposure to levels ofozone as low as 0.00010% are toxic. This can result in ozone or oxidantfeed requirements that are 10 to 100 times the stoichiometricrequirement.

Other available methods of removing contaminants from gases includeliquid absorbent scrubbers. Liquid scrubbers contact the airbornecontaminants with mist or fog that absorb or otherwise capture thecontaminant in the gas or air stream and remove it from the stream. Theair stream can then be safely vented to the atmosphere. All scrubbingliquids have a limit to the amount of contaminants they can absorb orcarry. Once the scrubbing liquid's capacity has been reached, the liquidmust be regenerated or discarded. Liquid scrubbers also frequentlyrequire expensive additives, such as metal chelates, defoamers, pHadditives, reactive agents or other specialty chemicals. Scrubbingliquids are frequently selective to specific contaminants making themimpractical for systems containing multiple contaminants.

Many industries have similar problems with treatment or disposal ofcontaminants from waste products. The-paint and coating industry isparticularly plagued with problems due to the nature of the paints andcoatings they use and produce. Many consumer and industrial itemsrequire coatings on the product. Such coatings are typically applied ina paint spray booth. A wide variety of coatings are in use todayincluding latexes, lacquers, varnishes, enamels, epoxies, polyurethanes,catalyzed coatings, metal-containing paints, and many more. Thesecoatings can be either oil based, solvent based, water based, solventwater emulsion based, or high solids catalyzed based (where the monomeracts as its own solvent for viscosity control). A paint spray booth isan enclosed ventilated area in which materials are sprayed or coated. Ascoating operations typically involve excess over-sprayed paintand-solvent vapors from the painting operation, the paint spray booth isintended to capture the over-spray while diluting the solvent vaporswell below the lower explosive limit as they are collected and exhaustedfrom the booth.

In water wash spray booths, forced air is used to direct the flow ofover-spray to a water wash chamber. The over-spray particulatecontaminants are trapped in the water wash scrubber section of the boothallowing the cleaned air to be vented or further processed. The waterwash solution is typically fresh water with various chemicals added todefoam, detackify and flocculate the collected over-spray. One popularwater wash booth solution is an oil-in-water emulsion. This emulsionsolution is particularly effective at capturing a wide variety of paintsin a paint spray booth. Various organic and synthetic oil systems arealso used in liquid scrubbers but have not found favor in the paintbooth scrubber application due to their cost and various recyclingproblems.

Peculiar to paint spray booths (as opposed to many other scrubberapplications) is the issue that the paint hardens or becomes tacky andsticky as solvent evaporates from the previously captured paintparticles. Paints that contact surfaces of the booth scrubber sectioncreate a film that grows thicker as deposits build up on the surface.Paint collected in air filters or in a wash section that is subjected toheat or drying becomes tacky. This causes, a problem in every aspect ofpaint booth operation, from the cleaning of equipment, walls and tanksto the further processing of removed sludge and solids. Water wash paintbooths typically capture the particulate contaminants in a suitableliquid material (usually water) by contacting the liquid with thecontaminants. Various chemicals are added to these liquids to providedetackifying properties. The addition of detackifying chemistry andflocculation chemistry increases the final sludge volume requiringdisposal by up to 300–400%. These chemical additions are expensive inthat they are costly to buy, require bath titrations and calculations todetermine the correct amount and frequency of addition needed tomaintain the booth, and increase the final disposal volume and cost byup to 400%. Since most industrial operations, including manufacturers,do some painting, the problems associated with painting operations arewidespread.

The paint industry also produces paint sludge and substantial quantitiesof unused paint that must be discarded. Currently, sludge from existingwater wash paint booths, and sludges from other industries that containhazardous organic ingredients, solvents or metals, require very specialand costly treatment. Separation of hazardous waste metals, water andorganics from various waste streams that vary substantially from batchto batch make separation process scaleups nearly impossible to consider.Premium disposal rates are charge for organic sludges with heavy metal(hazardous) contamination that have low BTU value due to water content.There is a need for a method of converting high-concentration paintwaste and sludge-like products with and without excess water contentinto useful or non-hazardous materials or by-products.

Manufactured items must first be cleaned in order to assure goodadhesion of the paint to the item. Manufactured components must becleaned of fabrication process surface contaminants such as fabricationoil, metal fines, shop dirt, dust and hand prints (oil). Thesecontaminants are typically removed with a cleaning fluid. When thecleaning fluid becomes saturated with contaminants, it must either bereconditioned or discarded. Reconditioning typically includes separationof the contaminants from the fluids so that the fluids can be re-used.The contaminants are then merely in a concentrated form and stillrequire disposal.

There is a need for a universal method and apparatus that addresses airpollution control and water pollution control such universal methodbeing applicable to treat volatile contaminants produced by a variety ofprocesses sources.

There is a need for a method and apparatus for converting hazardous,volatile and/or malodorous compounds into non-hazardous, less hazardous,non-volatile, less volatile, odorless and/or useful compounds.

There is a need for a method and an apparatus for cost-effectivetreatment of waste streams containing contaminants.

There is a need for a method of treating streams containing contaminantssuch that the contaminants are converted from hazardous to non-hazardousor less hazardous components.

There is a need for a method of oxidizing such contaminants involvingsubstantially reduced amounts of oxidizing reagent.

There is a need for an air pollution control process and apparatus thatcan efficiently treat streams with low concentrations of contaminants.

There is a need for air pollution control processes that do not produceadditional waste streams or waste products as a result of the pollutioncontrol process.

There is a need for a method and apparatus for the destruction orultimate disposal of multiple and/or mixed environmental contaminants.

There is a need for a liquid-scrubbing process and apparatus thatminimizes the cost of or need to regenerate the scrubbing liquid.

There is a need for a method and apparatus for detackifying scrubberliquids, sludges and the like.

There is a need for a method and apparatus for improving thefilterability of scrubber liquids, sludges and the like.

SUMMARY OF THE INVENTION

The present invention encompasses a universal method and apparatus forremoval and treatment of volatile, hazardous (including toxic) and/ormalodorous contaminants by converting the contaminants intonon-volatile, less volatile, non-hazardous, less hazardous, odorless,odor-pleasant and/or useful materials. Volatile contaminants orpotential volatile contaminants can be present in gas streams or inliquid streams. These contaminants may include those contaminantscategorized as volatile organic compounds (VOCs), volatile inorganiccompounds (VICs), malodorous compounds (MCs) and other air contaminantssuch as NO_(x)s and SO_(x)s that through chemical reaction may be madewater soluble, odorless or odor-pleasant, or otherwise non-volatile orless volatile. VICs include a variety of volatile inorganic componentsincluding inorganic siloxane solvents, newly introduced into commerce assubstitutes for VOCs, HAPs, malodorous compounds and ozone depletingsolvents used in the various manufacturing industries.

The present invention is universal in that it can be applied to modifycontaminants regardless of the phase of the carrier fluid, the volume ofthe contaminated stream, the mixtures of contaminants, or theconcentrations of contaminants. This makes the invention applicableacross all industries that produce harmful volatile contaminants,hazardous waste, and malodorous contaminants.

A method or process of treating a contaminated fluid having at least onecontaminant having a property selected from the group consisting ofbeing volatile, hazardous, tacky and a combination thereof is provided.The method comprises contacting the contaminated fluid with an effectiveamount of an agent selected from oxidizing agents, free radicalproducing agents and a combination thereof for an effective amount oftime to convert a substantial amount of the at least one contaminant toat least one corresponding modified contaminant having a propertyselected from the group consisting of being non-volatile, less volatilethan the contaminant, non-hazardous, less hazardous than thecontaminant, non-tacky and a combination thereof, and generating atreated fluid having a level of the at least one contaminant and of theat least one corresponding modified contaminant to allow the treatedfluid to at least meet requirements for release, reuse or furthertreatment.

The method may further comprise contacting a contaminated off-gascontaining the at least one contaminant with a contacting liquid toremove at least a substantial portion of the at least one contaminantfrom the contaminated off-gas generating a treated off-gas and thecontaminated fluid. The contaminated off-gas may be cooled prior to orduring the contacting with the contacting liquid to at least partiallycondense a portion of the at least one contaminant to facilitate removalthereof by the contacting liquid. A portion or all of the treated liquidmay be recycled-to the contacting liquid.

The method may further comprise stripping volatile contaminants from acontaminated liquid stream by contacting the contaminated liquid streamwith a stripping stream to generate a treated liquid stream and thecontaminated off-gas.

The method may be used with phosphating bath liquid. A preferred agentis the use of ozone. Ozone reacts with water to form peroxides thataccelerate phosphate coating formation. The ozone and water may be mixedprior to contacting the phosphating bath liquid. The ozone is preferablyadded in an effective amount to also act as a phosphate-coatingaccelerator, a secondary phosphate-coating accelerator compoundproducer, phosphate-coating accelerator compound regenerator orcombination thereof therein.

In view of the varied sources of contaminated fluids, the methods of thepresent invention may be integrated into such processes to providetreatment of such contaminated fluids. Accordingly, in a main processthat utilizes a contacting gas and generates at least one main off-gascontaining a contaminant, the process according to the presentinvention, for example, as shown in FIG. 2 may be used to treat suchmain off-gas as a contaminated off-gas. When there is a plurality ofmain off-gas streams, the plurality of main off-gas streams are combinedto form the contaminated off-gas. Additionally, at least a portion ofthe treated off-gas may be recycled to the main process as part of or asthe contacting gas.

Further, in a main process that utilizes a contacting liquid andgenerates at least one main liquid containing a contaminant, the processaccording to the present invention, for example, as shown in FIG. 1, maybe used to treat such main liquid as a contaminated fluid. When there isa plurality of main liquid streams, the plurality of main liquid streamsare combined to form the contaminated fluid. Additionally, at least aportion of the treated fluid may be recycled to the main process as partof or as the contacting liquid. In another embodiment, only a minorportion of the at least one main liquid is provided as a slip-stream fortreatment. This allows for a more continuous operation of the mainprocess.

One embodiment of the invention includes a liquid/gas scrubber orcontactor such that the agent (an oxygenation agent) is introduced intoa liquid carrying the contaminants where the oxygenation agentchemically alters the contaminants by adding one or more oxygen atoms tothe chemical structure of the contaminant. In this manner, the liquiddoes not become saturated with the contaminant thereby losing efficacy.The oxygenation agent is preferably introduced as a gas and in suchquantity that partial oxidation, rather than complete oxidation, occurs.This converts non-biodegradable compounds into biodegradable compoundsand volatile compounds into less volatile compounds and odor producingcompounds into less volatile and/or odorless compounds. Thus, the liquidscrubber also acts as a reaction vessel reactive product absorber and/orcondenser.

An alternate embodiment includes separate stages for the liquid I gasscrubber and the reactor stage with the oxygenation agent being added inthe reactor stage. The reactor would be a combination stripper/reactorin this embodiment as opposed to the scrubber reactor embodimentdescribed above. When the contaminants are already contained within aliquid, perhaps from a prior scrubber, contaminated ground water, orcontaminated process water, or other fluid, then the contaminated liquidcan be directed to the stripper/reactor stage. The stripper/reactorincludes introduction of contaminated liquids into a reaction vesselwhere the volatile contaminant is first encouraged to shift (flash) tothe gas phase where it is then partially oxygenated by reaction withozone, oxygen or other oxygenating reagent. The amount of ozone oroxygenating reagent used is limited such that preferably only thevolatile contaminants are reacted and converted to intermediateproducts. Said intermediate products include products that act assolvents, co-solvents, chelating agents, emulsifying agents (volatilecontaminants in scrubber fluid emulsifying agents), scrubber fluidsurface tension reducing agents, volatile contaminant volatilityreducing agents, non-hazardous materials and/or biodegradable materials.Furthermore, said intermediate products, having substantially lowervolatility and/or increased water solubility, shift back into the liquidphase via condensing and/or dissolving or absorbing in the liquid phaseand exit the reactor with the treated fluid in the liquid phase.

One preferred embodiment includes treatment ofwater-wash-paint-booth-wash water. By introducing the water of the boothinto the reactor of the invention, the contaminants are converted tointermediate products that enhance the scrubber solution used in thepaint booth. The reactor can be integral with the stripper or can be aseparate vessel. The regenerated solution can then be returned to thepaint booth, fed to a bioreactor, discharged to a local POTW (PubliclyOwned Treatment Works) for further treatment, a combination of theseitems or used in other ways. To avoid oversaturation of the wash waterwith intermediate products created by the oxygenation reaction, aslip-stream can be removed from the main wash water and treated suchthat the intermediate products are completely oxidized or theslip-stream can be removed to another location, such as bioreaction, forexample, in a bioreactor that converts the organic components in theslip-stream into methane biogas in an anaerobic bioconversion or intofertilizer in an aerobic bioconversion. When the slip-stream is removed,makeup water solution is added to the wash water. Makeup water solutionfor the water wash booth can be bioreactor treated and filtered waterthat is subsequently returned to the water wash booth, fresh water feed,or used rinse water from a cleaning process rinse. A particularlydesirable embodiment includes treating a slip-stream of the wash watersolution in the stripper/reactor rather than the entire volumesimultaneously. In this fashion, the stripper/reactor vessel size issubstantially reduced along with minimizing capital and operating costs.The stripper/reactor can then function during times when the paint boothis not in use, in addition or in place of those times when the booth isin use. The ozone generator capacity requirements are also minimized,for example, at least by a factor of 10, in this fashion furtherreducing costs of regeneration.

The stripper/reactor of the invention is also applicable to thetreatment of paint sludge and unused paint. These hazardous wasteproducts can be diluted with water before introduction into the reactorand exposure to the oxygenation reagent. Partly for safety reasons, theadded water acts as a thermal reaction rate regulator to minimize thepossibility of a runaway reaction, which could pose a fire or explosionhazard. Paint sludge and unused paint treated in this fashion arerendered non-hazardous just like paint booth sludge from a water washbooth. There are many possible uses for the product of treated paintsludge and unused paint. Further processing includes filtration (whichwould not be possible if solution was still tacky) for recovery ofvaluable pigments such as titanium dioxide, treatment in a bioreactor tocreate a saleable product, such as fertilizer from an aerobic bioreactoror methane biogas from an anaerobic bioreactor, and other recoveryoptions that will be specific to the type of valuable componentsinitially used or mixed into the original paint, sludge or unused paint.

The reactor of the invention is also useful in treating cleaning andphosphate baths. Cleaning baths used in many industries, particularlywhere metal is cleaned prior to painting, accumulate the contaminantsdiscussed above, oils, greases, solvents, metal fines, ionic metals andother soils. As described above, these cleaning solutions can beregenerated by oxygenation of the contaminants. Oxygenation creates acleaning solution with additional surface active components thusincreasing the specific emulsifying and soil carrying capacity of thecleaning solution. The reaction of the invention can take place in aseparate vessel that receives all or part of the cleaning bath to beregenerated, or the vessel used for the bath itself can be used as thereactor, or as one of the reactors. Furthermore, this invention includesthe addition of the oxygenation reagents (such as ozone) as phosphatecoating accelerators for the pre-paint metal finishing process in thephosphate coating bath. Furthermore, this invention includes theaddition of oxygenation reagents (such as ozone) that act as phosphatecoating accelerator compound regenerators (ClO₃ regeneration, forexample), and producers of secondary phosphate coating acceleratorcompounds such as peroxides and hydroxide free radicals. Since many ofthese phosphate coating processes are also parts cleaners (they containwetting and cleaning agents to disperse any remaining soils in order toinsure that a uniform phosphate coating is formed), the additionalbenefit of increasing the soil carrying capacity of the cleaner andtherefore extending the useful life of the cleaner—phosphate solution(by converting certain unsaturated and/or aromatic contaminants intoemulsifying and cleaning agents) is achieved, while extending andregenerating the phosphate coating solution's original phosphate coatingaccelerator compound. Both the phosphate coating accelerator and cleanerproperties must be regenerated to be able to reuse the phosphate coatingsolution. Typically, these phosphate coating parts cleaner baths arefrequently (sometimes weekly) dumped and replaced with new product.

The apparatus and method of the invention is useful for the capture andcontrol of a variety of cleaning and process solvent emissions such asthose containing o, m & p-xylenes, toluene, ethyl benzene, and variousketones, alcohols, acetates, esters, and other aromatic compounds.

Ground water, wastewater and process water are treated in a similarfashion. Reaction of target contaminants and reaction by-products withthe oxygenation reagent and reaction of target contaminants and reactionproducts with secondary oxygenation species formed by reactions ofoxygenation reagent with water creates a non-hazardous product availablefor use, re-use, further treatment or disposal. A preferred embodimentincludes the combined stripper/reactor discussed above where the contactwith the oxygenation reagent occurs in counter-current flow in astripper leading to reaction primarily in the gas phase and at the vaporliquid interface. Secondary oxygenation species formed by reaction ofthe oxygenation agent with water will react primarily in the liquidphase with less volatile and non-volatile compounds in the liquid phase.

Off-gasses, such as those produced by the burning of fossil fuel,emissions from bakeries and restaurants, and emissions from paint ovens,can be treated in another embodiment of the invention or captured in ascrubber first and then treated in the stripper/reactor as previouslydescribed. For off-gases that are already hot, one of the preferredembodiments would include a counter-current flow scrubber where the hotexhaust gases are progressively cooled and the scrubber liquid isprogressively heated as they both flow through the scrubber in acounter-current flow. Some volatile compounds would be condensed andtheir volatility reduced due to the temperature profile of the scrubber.The hot gas feed would tend to re-volatize the condensed volatilesleading to an increased concentration of volatile contaminants in thescrubber. By feeding the oxygenation reagent into the scrubber at apoint between the gas and liquid feeds where the accumulating volatilecontaminant is still volatile, it can be reacted with the oxygenationreagent in the gas phase. This results in a scrubber/reactor combinationembodiment as distinguished from the previously describedstripper/reactor. Cleaned off-gas is exhausted from the scrubber/reactorto further treatment, if needed, re-used or vented to the atmosphere.Heat recovery is possible from the scrubber liquid. After the scrubberliquid is cooled, the scrubber liquid can be re-used in thescrubber/reactor. Scrubber/reactor and stripper/reactor combinations arealso possible and can be combined to increase ultimate process captureefficiency. In such a case, the scrubber liquid and stripper liquidwould circulate in a loop with the off-gas contaminated exhaust feed tothe scrubber being the source of volatile contaminants being capturedand controlled. The result of combining both embodiments is a gas streammeeting regulatory requirements and a liquid stream that has beenregenerated.

An alternate embodiment would include the treatment of sticky tackyfluids, flowable sludges and wastes (perhaps with prior dilution to forma pumpable solution) with poor filtration properties. By treating thesematerials first with the stripper/reactor process, and therebydetackifying the solution, filtration of the resultant detackifiedsolution is enabled. In some cases, a partial polymerization andaggregation of molecules will occur as well as improving thefilterability of the solution This is in addition to other possiblebenefits described above. Filtration of sticky tacky paint contaminatedpaint booth wash water and similar sticky tacky used contaminatedscrubber liquids, and other similar process or waste liquids and sludgesis not possible or economical unless they are first some howdetackified. Water wash paint booths have in the past been detackifiedusing chemical additives such as clays, organic detackifiers, polymersand flocculates at substantial cost to the customer.

The current invention is useful in recovery of pigments, polymers,metals and other valuable materials in paint. Effective recovery throughfiltration is made possible through the detackification of paintingredients. Detackification includes reacting the paint or coatingwaste product with the oxygenation reagent of the invention such thatdetackification occurs. For paints containing reactive monomers,detackification includes at least partial polymerization of suchmonomers. Detackification also includes the aggregation of paintingredients.

Due to the universal nature of the invention, contaminants of varioussources can be combined for treatment. For example, off gases from wetpaint water wash paint booths can be combined with the off gasses fromthe bake oven used to dry the painted parts and/or the paint sludgeand/or the vent gases from solvent-based parts washers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow schematic of an embodiment of the present invention.

FIG. 2 is a flow schematic of another embodiment of the presentinvention.

FIG. 3 is a flow schematic of a heat exchanger used in the presentinvention.

FIG. 4 is a flow schematic of another embodiment of the presentinvention adding to that shown in FIG. 2 a filtering step and recycle ofthe treated and/or filtered streams.

FIG. 5 is a flow schematic of another embodiment of the presentinvention adding to that shown in FIG. 1 a filter and bioreactor.

FIG. 6 is a flow schematic of another embodiment of the presentinvention adding to that shown in FIG. 2 a stripping step.

FIG. 7 is a flow schematic of another embodiment of the presentinvention similar to that shown in FIG. 6, but only utilizing a singlevessel as a stripper/reactor.

FIG. 8 is a flow schematic of another embodiment of the presentinvention similar to that shown in FIG. 7 with the addition of abioreactor.

FIG. 9 is a flow schematic of another embodiment of the presentinvention

Among the Figures, like numerals designate like or similar items.

So that the manner in which the above-recited features, advantages andobjectives of the invention, as well as others which will becomeapparent, are attained and can be understood in detail a more particulardescription of the invention briefly summarized above may be had byreference to the embodiments thereof illustrated in the drawings, whichdrawings form a part of this specification. It is to be noted, however,that the appended drawings illustrate only preferred embodiments of theinvention and are, therefore, not to be considered limiting of theinvention's scope, for the invention may admit to other equallyeffective embodiments.

DETAILED DESCRIPTION OF THE INVENTION

The current invention includes a process and apparatus for reacting thecontaminants with an oxygenation source to convert the contaminantsprimarily to intermediate products with desirable characteristics. Bycontacting volatile organic contaminants with the limited oxygenationsource, such molecules are converted into compounds that preferably arethemselves much less volatile or non-volatile. This limited reactionproduces a range of products, depending on the contaminants. Ketones,aldehydes, alcohols, polyols and compounds containing carboxylic acidand/or carbonyl functional group(s) can result. By controlling andlimiting the oxygenation reaction to create the intermediate productssuch as the salts of carboxylic acids, di-acids, polyols and amphotericcompounds such as diacid polyols and the like, the contaminants aremodified into components that act as volatile compound absorbents thatcan emulsify additional volatile components, that would not be otherwisecaptured, into the scrubber solution.

The invention is applicable to many varied applications. Examples ofsuch applications include, but are not limited to, paint spray boothpollution control paint sludge and excess paint disposal,detackification of paint sludge, water wash paint booth scrubbersolution, liquefied industrial sludges, cleaning solvent, such as thoseuseful to clean metal parts prior to painting, off-gas vent control,ground water remediation, process water or wastewater treatment, off-gastreatment such as from a process using fossil fuel, off-gas treatmentfor bakeries and restaurants, and other applications where the volatilecompounds occur in vapor or liquid form such that a disposal or recoveryneed arises.

A method of treating a contaminated fluid 10 having at least onecontaminant having a property selected from the group consisting ofbeing volatile, hazardous, tacky and a combination thereof is provided.Referring now to FIG. 1, the method comprises contacting thecontaminated fluid 10 with an effective amount of an agent 12 andgenerating a treated fluid 14. The agent 12 is selected from the groupconsisting of oxidizing agents, free radical producing agents and acombination thereof. The contaminated fluid 10 is contacted with theagent 12 in at least one vessel 16 for an effective amount of time toconvert a substantial amount of the at least one contaminant to at leastone corresponding modified contaminant. The contaminated fluid 10 andthe agent 12 may be contacted counter-currently or co-currently. Themodified contaminant has a property selected from the group consistingof being non-volatile, less volatile than the contaminant,non-hazardous, less hazardous than the contaminant, non-tacky and acombination thereof. The treated fluid 14 has a level of the at leastone contaminant and of the at least one corresponding modifiedcontaminant to allow the treated fluid 14 to at least meet requirementsfor release, reuse or further treatment. The contaminated fluid 10 andthe treated fluid 14 may be in a gaseous or liquid form. The vessel 16may be a reactor.

The agent 12 may be contained in a carrier with which it may be reactiveor not. The agent 12 can be a free radical producing agent, for example,selected from the group of free radical initiators, free radicalpropagators and combinations thereof. The free radical producing agentmay be a peroxide, which may be an organic peroxide, an inorganicperoxide or combinations thereof. The peroxide may be added or formed insitu. In the latter case, ozone produces hydrogen peroxide in water.

The agent 12 may be an oxidizing agent. A preferred oxidizing agent isozone. In some cases, ozone may be referred to as activated oxygen.Other oxidizing agents include potassium permanganate and periodic acid.

Referring now to FIG. 5, the method may further include the step offiltering the treated fluid 14 to generate a filtered fluid 32 andcollected materials 34. The filtered fluid 32 may then be fed to abioreactor 50 for bioconversion to bioproducts 52. The bioreactor 50 maybe an anaerobic bioreator, an aerobic bioreactor or a combinationthereof. The bioproducts 52 include, but are not limited to, biotreatedwater, biogas containing methane and fertilizer.

When the at least one contaminant is tacky, the effective amount of theagent 12 is an amount that detackifies such tacky contaminant.

Referring now to FIG. 2, there is shown another embodiment of thepresent invention, which adds onto that shown in FIG. 1. In thisembodiment, the method further comprises contacting of a contaminatedoff-gas 18 with a contacting liquid 20 generating a treated off-gas 29and the contaminated fluid 10. The contaminated off-gas 18 contains atleast one contaminant. During such contacting, the contacting liquid 20removes at least a substantial portion of the at least one contaminantfrom the contaminated off-gas 18. The contaminated off-gas 18 and thecontacting liquid 20 can be contacted counter-currently or co-currently.The contacting may occur in a scrubber 22.

Referring now to FIGS. 2 and 3, the method may further comprise coolinga hot contaminated off-gas 28 resulting in the contaminated off-gas 18prior to contacting with the contacting liquid 20. The cooling is usedto at least partially condense a portion of the at least one contaminantto facilitate removal thereof by the contacting liquid 20. This may bedone using a heat exchanger 24 with a cooling source 26. Alternatively,or in addition thereto, the contaminated off-gas 18 may be cooled bycontacting it with the contacting liquid 20 that is cooler than thecontaminated off-gas 18 to at least partially condense a portion of theat least one contaminant to facilitate removal thereof by the contactingliquid 20.

The contaminated off-gas 18 is generated by a variety of processes andestablishments. General examples include, but are not limited to,off-gases from industrial processes, pharmaceutical processes, solventcleaning processes, solvent degreasing processes, fiberglass operations,ink and printing operations, wood and wood products drying processes,food industries, rinsing processes and paper mills. Specific examplesinclude, but are not limited to, off-gases from paint shops, bakeries,restaurants, dry cleaners and burning of fossil fuel. These are toosmall to be presently regulated due to the high costs associated withconventional technology, but are particularly suited for treatment withthe methods of the present invention in a cost-effective manner.

Referring now to FIG. 4, the method shown in FIG. 3 is modified in oneor more ways. For example, the method may further comprise filtering thetreated liquid 14 using a separating device 30 to generate a filteredliquid 32 and collected materials 34. The method may further compriserecycling at least a portion of the treated liquid 14 to the contactingliquid 20, which is referred to as a recycled treated liquid 36.Alternatively, or in addition thereto, the method may include recyclingat least a portion of the filtered liquid 32 to the contacting liquid20, which is referred to as a recycled filtered liquid 38.

Referring now to FIG. 6, the method shown in FIG. 2 may be furthercomprise stripping volatile contaminants from a contaminated liquidstream 40 by contacting the contaminated liquid stream 40 with astripping stream 42 to generate a treated liquid stream 44 and thecontaminated off-gas 18. Such contacting may occur within a vesselcalled a stripper 46. The stripping stream 42 may be any gaseous streamcapable of removing such volatile contaminants, and is preferablyselected from the group consisting of air, steam and a mixture thereof.The stirring stream 42 may contain or be the agent 12.

Referring now to FIGS. 6 and 7, when the treated liquid stream 44 is thecontacting liquid 20, the method may be performed in a single vesselcalled a stripper/reactor 48. The contaminated liquid stream 40 may befed at or near the top of the vessel 48 and the stripping stream 42 isfed at or near the bottom of the vessel 48. Preferably, the agent 12 isfeed at a point between the top and bottom of the vessel 48. The treatedoff-gas 29 exits at or near the top of the vessel 48. The treated fluid10 exits at or near the bottom of the vessel 48. The contaminated fluid10 and the contaminated off-gas 18 are internalized to the vessel 48,and accordingly not shown.

Referring now to FIG. 8 which is a modification of FIG. 7, the treatedfluid 14 can be fed to a bioreactor 50 to generate bioproducts 52. Thetreated off-gas 29 can also be fed to the bioreactor 50. This ispreferable when the treated off-gas 29 has an oxygen concentrationgreater than ambient air.

Referring again to FIG. 1, the contaminated fluid 10 may be contaminatedair or contaminated water. The are many sources of both. Thecontaminated air may be the contaminated off-gas discussed previously.Contaminated water includes, but is not limited to, water that containspaint, water that contains paint-related solvents, cleaning bath liquid,phosphating bath liquid, ground water, wastewater, process water, rinsewater, scrubber water and combinations thereof.

One type of contaminated water of interest herein is water that containspaint and/or paint-related solvents. Sometimes this type of contaminatedwater also contains a floating contaminant. In this situation, themethod may further comprise removing the floating contaminant prior tocontact with the agent to generate a skimmed water stream and skimmedcontaminant. Water that contains paint poses a special treatment problemof containing contaminants that are tacky and cause problems withfiltering or other removal techniques for removing such contaminants. Inthis case, the agent 12 preferably has the additional property ofdetackifying the tacky components in paint. The agent 12 is added in aneffective amount to also detackify such tacky components. Thereafter,the method may include the step of filtering the treated fluid 14 (whichis a liquid) to generate a filtered liquid 32 and a recovered material34, for example, using a separating device 30, similar to the firstportion of FIG. 5 without the bioreactor 50. The recovered material 34may then be separated to recover desired materials therefrom thatinclude, but are not limited to, pigments, monomers, metals andcombinations thereof. At this point, the monomers may also includeoligomers or partially polymerized monomers.

A particular source for the water that contains paint is wash water froma paint booth and also paint sludge. Likewise, in the paint industry, aproblem exists with disposal of excess paint or used paint and/or paintsludge. In this case, the water that contains paint may be obtained bycombining water with paint and/or paint sludge that requires disposaland utilizing the method of the present invention.

Another source of contaminated water which is of particular interest isa phosphating bath liquid. A preferred agent in this case is ozone. Theozone reacts with water to form peroxides that accelerate phosphatecoating formation. In one embodiment, the ozone and water are mixedprior to contacting the phosphating bath liquid, which is sometimesreferred to as ozonated water. An additional benefit of using ozone orozonated water is that the ozone may be added in an effective amount toalso act as a phosphate-coating accelerator, a secondaryphosphate-coating accelerator compound producer, phosphate-coatingaccelerator compound regenerator or combination thereof therein. Theozone may be added in an effective amount to act as thephosphate-coating accelerator therein, thereby replacing conventionalaccelerators that pose disposal problems and may be toxic. In such asituation, the ozone will also cause the production of secondaryaccelerators in situ, for example, hydrogen peroxide.

In view of the varied sources of contaminated fluids 10, the methods ofthe present invention may be integrated into such processes to providetreatment of such contaminated fluids 10. Accordingly, in a main processthat utilizes a contacting gas and generates at least one main off-gascontaining a contaminant, the process according to the presentinvention, for example, as shown in FIG. 2 may be used to treat suchmain off-gas as a contaminated off-gas 18. When there is a plurality ofmain off-gas streams, the plurality of main off-gas streams are combinedto form the contaminated off-gas 18. Additionally, at least a portion ofthe treated off-gas may be recycled to the main process as part of or asthe contacting gas.

Further, in a main process that utilizes a contacting liquid andgenerates at least one main liquid containing a contaminant, the processaccording to the present invention, for example, as shown in FIG. 1, maybe used to treat such main liquid as a contaminated fluid 10. When thereis a plurality of main liquid streams, the plurality of main liquidstreams are combined to form the contaminated fluid 10. Additionally, atleast a portion of the treated fluid may be recycled to the main processas part of or as the contacting liquid. In another embodiment, only aminor portion of the at least one main liquid is provided as aslip-stream for treatment. This allows for a more continuous operationof the main process.

An example of a main process situation incorporating the presentinvention is shown in FIG. 9. One preferred embodiment of the inventionintegrates many of the fluid and heating processes in a paintingoperation and thereby reduces water consumption and the generation ofwastewater. Water wash paint spray booth scrubbers evaporate largeamounts of water. Heated solutions of cleaners, phosphating solutions,rinses and dry off ovens also loose water to evaporation. Any scrubber,scrubber/reactor, or scrubber reactor condenser added to the exhaust ofa paint line bake oven, or integrated feeds from a coating operationwill also loose water to evaporation as a normal part of the process.Furthermore rinse waters are typically overflowed to keep soluble solidsin solution from reaching the supersaturation point so thatprecipitation and scaling are eliminated or minimized.

In this preferred embodiment overflowed rinse waters are reused as makeup water to replace water lost to evaporation in the cleaner bath(s),phosphating bath(s), paint bake oven off-gas scrubber(s), and water washpaint spray booth(s). In this manner water consumption is minimized,surfactants and contaminates that are collected in the rinse water arereused in the cleaner, phosphating, paint bake oven off-gas scrubber,and water wash paint spray booth(s) and waste water disposal and relatedcosts are further minimized.

Furthermore pretreatment of raw water feed using a water softener willreduce rinse water requirements, and surfactant consumption(precipitation of hard water scum).

Excess surfactants from the regenerated cleaning solution bath can beused by bleeding any excess to one of the water wash paint spray boothscrubbers, paint bake oven(s), phosphating bath(s), visa versa, or evenmixed (blended) to create a mixed solution where VC absorption andadsorption properties, cleaner emulsification and solubilizationproperties and detakification of contaminates are maximized, whiledynamic surface tension properties are minimized.

Finally, integration of the water wash paint booth's recyclic fluidregeneration reactor with the paint bake oven's recyclic fluid scrubberreactor would include heat recovery. In situations where it is desirableto heat the fluid feed to the water wash paint booth scrubber's recyclicfluid regeneration reactor to improve the flash of VCs in the reactorinto the gas phase, recovered heat from the paint bake oven's recyclicfluid scrubber reactor would be used with a heat recovery heat exchangerto-reduce the heat input required for the water wash paint boothscrubber's recyclic fluid regeneration reactor. In cases where the waterwash paint booths recyclic scrubber fluid is heated it would beadvantageous to cool the fluid before returning it to the water washpaint booth scrubber. In this case cool exhaust air from the dischargeof the paint booth exhaust would be used to cool the returningregenerated recyclic scrubber fluid before it is reintroduced back intothe water wash paint booth scrubber using an air cooled heat exchanger.

An alternate embodiment would use the bake oven's recovered heat toreduce the input heat requirements for drying washed parts in the dryerstage before paint application in the paint booth, the heated cleaningsolution, the heated phosphating bath, or to reduce heating requirementsused to increase the VC flashing stage of the water wash paint booth'srecyclic fluid regeneration reactor. By detakifying these fluids the useof heat exchangers becomes economically viable since the non-fouling,detakified, non-supersaturated fluids will keep the heat exchangersurfaces clean and energy efficient.

The scrubber 22 of the current invention can be a traditional scrubber,such as a water wash as in a paint spray booth, an electrostaticprecipitator, a venturi scrubber or other traditional apparatus. Apreferred embodiment includes an air or gas pretreatment step where thetemperature and/or pressure are manipulated prior to scrubbing.Depending on the character of the contaminated gas or liquid stream,mechanical filtration can also be performed. For example, skimming canbe utilized to remove large amounts of contaminants with the remainingliquid being treated in a stripper reactor. The skimmed material can befurther processed in the same manner as paint sludge herein to convertthe contaminants therein into compounds that are less hazardous ornon-hazardous, and/or as a feed to a bioreactor 50. In this manner,costs can be minimized while concentrations of VCs are minimized oreliminated.

Another preferred embodiment includes further treatment after thescrubbing process, such treatment removing additional or differentcontaminants. Thus, post treatment can include an adsorber, biofilter orother additional contaminant-capturing device. The air or gas stream,jointly referred to as air stream, can also be subjected to electronbeam, ultrasonics, magnetic field or electromagnetic radiations. Thescrubbed air stream (treated off-gas 29), whether or not post treated,is then vented to the atmosphere or recirculated or used as an oxygensource for an aerobic bioreactor, as desired. Oxygen concentration inthe liquid sparged phase of aerobic bioreactors follows Henry's Law,thereby limiting treatment rates. However, if the oxygen concentrationin the oxygen-containing stream fed to the bioreactor is higher thanambient, then the maximum oxygen concentration in the bioreactor liquidis raised proportionally, reducing the required bioreactor volume.Therefore, in cases where the scrubbed air stream has an oxygenconcentration higher than ambient, such a stream would have theadditional benefit of allowing the use of a smaller reaction volume forthe bioreactor. Thus, additional acquisition capital savings could berealized on the bioreactor.

The bioreactor 50 can be an anaerobic reactor used to produce methanebiogas that can be used to fire bake ovens on a paint line, or bakeryovens or the like. The bioreactor can also be aerobic, a combination ofaerobic and anaerobic stages tied together in series or parallel.Fluidized bed bioreactors, biologically activated carbon filters,biologically activated carbon fluidized bed reactors, biotricklingfilters, packed bio-active columns, biologically active sand filters,biologically active fluidized bed media filters (sand and the like),activated sludge bioreactors, rotating biological contactor disks andthe like can be used individually or in various combinations dependingon the application.

The scrubber liquid (contacting liquid 20) of the invention can bewater, organic liquid or inorganic liquid. The scrubber liquid can beinert to reaction with the contaminants, and/or oxygenation agent (agent12). The liquid can be blended specifically for the target contaminantsand can include other additives such as enzymes, surfactants,oxygenation reagents, oxygenation reactive additives and catalysts. Whenthe contaminants are in the air stream, the liquid scrubber fluid iscontacted with the air stream carrying the contaminants (contaminatedoff-gas 18) such that the contaminants are transferred into the liquidfluid. The liquid scrubber fluid with contaminants (contaminated fluid10) enters the reactor 16 where the contaminants undergo conversionthrough oxygenation. In a preferred embodiment, oxygenation is performedusing agents 12 such as ozone, peroxide, oxygen, catalysts, activatedoxygen, electrolysis, enzymes or any combination thereof Oxygenationresults in creation of less-volatile components. These components can befurther treated if desirable, or discharged, or used to capture morevolatile contaminants. As oxygenation creates products that act assurface active agents, emulsifiers or solvents, the liquid scrubberfluid can be enhanced in volatile contaminant absorbing capacity by suchprocess. In such case, the liquid scrubber fluid is returned to theprocess carrying the products of the conversion of the contaminants,such a recycle streams, 36 nad 38 in FIG. 4.

One preferred embodiment of the scrubber of the invention is a dualstripper/reactor that is a vertical tower 48 (FIG. 7). The contaminatedliquid 20, such as wastewater, ground water or contaminated scrubberfluid, enters the tower 48 from the top, for example, as a gravity feedor pressurized feed. Where the reagent is volatile, such as ozone,reagent gas is fed counter-current to the liquid stream. Acounter-current stripper/reagent gas stream is fed at the bottom of thetower. A vapor liquid exchange occurs within the tower leading volatilecontaminants to come into contact with the ozone or oxygenation reagentcontained in the reagent gas stream and react to form less hazardous ornon-hazardous, usable, biodegradable, or less volatile or non-volatilematerials. Wastewater treated in such manner is then suitable fordisposal, heat recovery, filtration, further treatment or for re-use.Liquid scrubber fluid treated in such manner is ready for re-use, heatrecovery, filtration or disposal.

Another alternate embodiment includes separate stripping and reactionstages or vessels where the reaction stage permits reaction withcontaminants in the gas phase. The stripping stage is used to remove orflash the volatile contaminants from the liquid wastewater or scrubberfluid (liquid) stream. The volatile contaminants removed by the airstream or steam stripping are then fed to the reactor stage. Reagentssuch as ozone, ozone/water reaction decay oxygenation products such assuper oxide radical anion, HO₂ (hydroperoxide radical), ozonide radicalion, hydrogen peroxide, organic peroxides formed by reaction withcontaminants, organic peroxides, UV radiation, other oxygenationreagents, or radicals such as hydroxyl free radicals or organic radicalsare then used to treat the air stream. Typically, the reaction productscondense, dissolve, and/or are absorbed or adsorbed by the scrubberliquid.

One of the reactions believed to occur is direct oxidation of thecontaminant such that carbon-carbon double or triple bonds (i.e., Pibonds) are attacked by the oxygenation reagent. Unlike other reactionswhere the carbon skeleton of the starting material is left intact, ozonecan open alternating double bonded aromatic ring structured compoundsforming unstable ozonides. These ozonides further decay after combiningwith water to typically form two new compounds. One compound has acarbonyl functionality such as an aldehyde or ketone. The secondcompound is a Zwitterion (II) that quickly leads to ahydroxy-hydroperoxide (III) stage that in turn decomposes into acarbonyl compound and hydrogen peroxide. Hydrogen peroxide formed fromozonide decay and from ozone reaction with water can react as anoxidizing agent, reducing agent and or free radical reaction reagent andpromoter. The oxygenated end of the molecules created creates a moleculewith a polar (water loving) end. The other end remains a non-polar end.Those molecules having one polar end and one non-polar end (oil loving)act as surfactants. The non-polar oleophilic end will be hydrophobic andbe attracted to other organic molecules, while the carbonyl end will behydrophilic and attracted to water and other polar compounds, allowingthe molecule to act as a surfactant. Other strong oxidizing agentsuseful in the invention include potassium permanganate and periodicacid. Other contaminants, such as diols, undergo similar reactions. Asthere are large numbers of possible compounds that are VCs, there areequally numerous non-volatile compounds that can result from thisreaction.

There are multiple sources of contaminants associated with paint boothuse. Paint ovens also give off VCs in the oven exhaust These off-gasescan be routed to a separate scrubber or combined with other scrubberoperations available for the paint line. Likewise, wash water inpainting operations can include VCs. The VCs can be volatized andcombined with the other scrubber operations, fed to a stripper reactor,or contacted in a liquid/liquid separation system.

One embodiment of the invention uses an oil-in-water emulsion system tohandle the contaminants. Prior art shows that paint particulatecontaminants are brought into contact with such an emulsion, in a liquidgas scrubber called a water wash paint spray booth, primarily to capturepaint particulate. The VOCs attach (absorbed) to the oil in the emulsionuntil equilibrium saturation occurs at which point the emulsion releasesVOCs as fast as it captures them. VOC capture is not the designobjective in existing systems of this type. The emulsion is then pHshifted by traditional means to break the emulsion. Steam stripping isused to separate the incidental VOCs from the oil phase such that theoil is returned to the emulsion. VOCs released are then treated insecondary operations such as condensation, activated carbon adsorptionor incineration. These steps have been or are currently being used insome paint booths.

The current invention includes the step of subjecting the concentratedVOCs to reaction with ozone, secondary ozone reaction products, or otheroxygenating reagent in such quantity that a large portion of thevolatile contaminants are converted in part to useful products, asdiscussed above. These useful products are returned to the emulsionsystem to improve the absorption and adsorption capacity of such systemand to maintain the life of the scrubber solution. This reaction lowersthe VCs activity and volatility by increasing or adding hydrogen bonding(water loving) ability to the VC contaminant by combining thecontaminant with molecular oxygen, thereby increasing the reacted VCssolubility in the hydrophilic (water loving) portion of the scrubberliquid. After contacting the fluid to the contaminant, the fluid beingany liquid carrier such as an emulsion, a hydrotropic, blended or otherfluid, the contaminated fluid enters the reactor. The used scrubberliquid is reacted as described above to create a cleaning and absorbingand adsorbing scrubber solution with substantially reduced contaminantcontent and with conversion of those contaminants to useful ornon-hazardous components. The reacted scrubber fluid is then availableto be placed back into the scrubbing chamber for re-use. Use oroperation of the reactor may also be combined with additionaltraditional steps, such as pH adjustment, manipulation of temperature orpressure, filtration, flocculation, precipitation, skimming,electrolysis, electromagnetic exposure and other steps. Alternatively,the material can be discarded as non-hazardous waste. Such waste productcan be used as a feed source for a bioreactor in creation of a biomassfertilizer or a biogas, such as methane. A preferred embodiment includesgathering the liquid stream in a sump, i.e., an equalization tank, suchthat the feed can be measured and controlled to the reactor to avoidaccidental overload.

A preferred embodiment includes temperature, pressure, liquid dynamicsurface tension, flow rate, oxygenation reagent concentration, liquidturbidity, contaminant concentration, COD, BOD, TOC, reaction residencetime and the like, measurement and control for optimization of theoperation. The reactor can be in continuous, batch or continuous batchmode, one or multiple stages.

The invention permits of multiple embodiments with varying degrees ofcontrol over the progress of the oxygenation reaction. As describedabove, a slip-stream can be sent to the reactor such that the reactoracts in a continuous batch mode. In this manner, small amounts of theoxygenation reagent can be added over a long-period of time, which hasan added benefit of reducing equipment sizes and associated capitalacquisition costs. In situations where the amounts of contaminants varybased on usage, the amount of the oxygenation reagent and the length ofresidence time leading to oxygenation can be controlled and varied tolimit the consumption of oxygenation reagent and to limit thedestructive losses of useful organic agents already added or produced bythe process.

In situations where it is highly desirable to monitor the amount ofcontaminants being converted or the build-up of surface active agents inthe solution, the amount of contaminants captured is measured.Traditional methods of monitoring can be used. Since the composition ofpaints is complex, actual compositional analysis is rarely costeffective. This invention includes an optional method of monitoring thecontaminants captured in liquid to assure that the liquid is exposed toan appropriate amount of oxygenation reagent. A method of monitoringcontaminants can include performing a mass balance on the scrubberfluid, for example, the paint spray booth wash water, to determine theChemical Oxygen Demand (COD) or Total Organic Carbon (TOC) of thematerial captured or contained therein as compared to the COD or TOCprior to capture. Other useful information for process control includedynamic surface tension, temperature, pressure, turbidity, pH,contaminant(s) concentration, and surfactant(s) concentration, whetheradded or produced in situ. By applying and comparing historical and/ortest data specific to the process including the COD or TOC information,the amount of oxygenation reagent can be empirically controlled usingsuch information to produce the desired reaction of contaminants.Furthermore, credit can be taken after documenting the capture of saidVCs in annual emissions inventories based on such mass balanceinformation.

Paint ovens, bakeries, restaurants and other industries emit VCs fromthe baking or heating operations. These are released in the form ofexhaust gas. These off-gases are routed through the scrubber reactor ingaseous form as described above. The off-gases can be collected into onecentral location where necessary. An alternate embodiment includescontacting the contaminated off-gas with scrubbing fluid such thatcontaminants are transferred to the scrubbing fluid. The contaminatedscrubbing fluid can then be introduced to the stripper reactor forreaction with the oxygenation reagent. In this manner, it is alsoeffective to combine the contaminated liquids of the system The off-gascaptured contaminants, from the oven scrubber or scrubber reactor, canbe combined with the contaminants from the water wash paint boothscrubber and wash lines that would then be treated in the reactor toregenerate the wash scrubber liquid.

Another embodiment relates to metal washing liquids. When steel partsare to be painted, oil, grease and metal shavings must first be removedand the surface made receptive to the adhesion of paint. This process istypically performed using a spray wash of a soapy alkaline solutionfollowed by a rinsing step. The resulting effluent may contain some ofthe volatile contaminants along with various oils and greases. Thiseffluent can be treated as described above either by routing to thescrubber/reactor, stripper/reactor or by using the existing cleaningsolution holding tank in which processing takes place as the reactorvessel.

Additional steps are performed to further clean organics off of themetal part to be washed and to finish the surface in such a fashion thatpaint will adhere. For example, within the coating arena is aspecialization involving phosphate conversion coating prepaint treatmentbaths. These baths depend upon oxidizing agents in the bath toaccelerate or catalyze the formation of a metalic phosphate film on thetarget object. Standard art includes the use of sodium nitrate, sodiumnitrite, hydrofluoric acid, nitrobenzene sulfonate, sodium chlorate orthe like to catalyze the reaction. Such baths are typically operated atpHs between 3.0 and 6.0. All of these components create waste disposalproblems of various magnitudes with nitrobenzene sulfonate being toxic.The present invention includes the use of ozone in he bath in place ofor in addition to prior art catalysts or oxidizers.

Another problem is that the phosphate bath begins to accumulatecontaminants from the metal parts and from carry over of the previouswashing and rinsing steps. These contaminants eventually interfere withthe solution requiring regeneration or disposal of solution. With ozone,the benefits described above are achieved in that organic contaminantsare washed off the parts and are reacted to create useful andnon-hazardous components. For example, they are converted into compoundsthat increase the soil and contaminant holding, emulsifying andsuspending capacity of the phosphate cleaning bath. By oxygenating someof the contaminants and organic compounds, surfactants are producedwhich increase the soil holding, emulsifying and dirt suspendingcapacity of the bath and thus increases bath life of the solution.

Another surprising effect of adding ozone to the phosphate bath is thatthe ozone acts as an oxidizer accelerator, thereby eliminating the needfor nitrobenzene sulfonate or the like. Thus, the present inventionincludes the use of ozone in the bath in place of prior catalysts oroxidizers, or to regenerate reduced oxidizer accelerators therebyextending the useful life of the bath. The added benefit seen whenapplying the current invention to the phosphate solution includes theuse of ozone as the oxidizer accelerator, thus avoiding the addition ofless desirable compounds.

Another benefit of using ozone in the phosphate solution is theproduction of secondary inorganic and/or organic oxidizers, free radicalinitiators, propagators, accelerators and/or catalysts resulting fromthe reaction of ozone with water and/or other compounds in the water.This avoids the addition of less desirable compounds and/or extendingthe useful life of the phosphate cleaning bath.

Typically, the metal part is immersed into a tank containing or sprayedwith the phosphate bath such that the surface of the part becomes coatedwith an iron, zinc or the like phosphate film by reaction of the bathwith the metal surface of the part. While the phosphate bath liquid canbe introduced into the reactor described above and then recycled to thebath, an alternate embodiment is to add ozone directly to the phosphatebath and/or to the phosphate bath washer while the parts washing spraysystem is in operation. Using the spray washer as a means of contactingthe phosphate bath with the ozone, eliminates additional contactingequipment and provides the associated cost savings. In a spray phosphatewasher, the ozone can be introduced in the gas phase to the spray partswasher spray phosphating section such that sprayed liquid interacts withgaseous ozone as it contacts the metal parts being washed andphosphated. In this fashion, contaminants and soil in the solution areconverted and the oxygenation phosphate coating acceleration reactiongoes forward. Some ozone will react with water forming peroxides in theliquid phase. Peroxides can also accelerate the phosphate coatingformation. Alternatively, “ozonated water” can be prepared by mixingozone with water creating hydrogen peroxide in situ. The ozonated watercan then be fed to the phosphate bath or to the phosphate bath washer.

The reactor of the invention permits oxygenation of the contaminantsthrough chemical reaction with ozone, peroxide, catalyst, electrolysis,enzymes or any combination thereof. When using a gaseous oxygenationreagent such as ozone, the gas is typically fed in counter-current tothe liquid stream containing the contaminants. One particular method ofcreating ozone content is to treat the input air stream containingoxygen to the reactor by corona discharge reaction, exposure to UV,electrolytic ozone generators or other known methods of creating ozone.The amount of ozone used is less than that required for sterilization ortotal destruction of contaminants. It is undesirable for economic andecological reasons to use excess ozone. In a preferred embodiment, ozoneis totally consumed (i.e., reacted) in the reactor(s) and/or bioreactorprior to exhaust gas venting to the atmosphere or recycling of the ventgas.

Paint booth water builds up with paint particles that are sticky andmust be chemically detackified. Ozone and other-oxygenation reagents, inchemically changing that part that makes the paint sticky and tacky,detackify the water wash paint booth water. Thus, oxygenation serves todetackify the paint providing a benefit additional to that of themodification of the volatile contaminants targeted. Apart fromconversion to non-volatile and less volatile compounds to meetregulatory and re-use requirements, the present invention is useful fordetackifying paint. This in turn permits recovery of useful by-products,use of various separation techniques and other processes that wouldotherwise be inappropriate due to the tacky consistency of paint. Thischemical change improves the filterability of the liquid and alsoalleviates the adhesion of residue on water wash paint booth holdingvessels and the like. Typically, water wash paint booth holding vesselsand the like must be replaced every three years due to the nature of thebuildup and associated corrosion that results.

It is believed that in part damage to the vessels is due to anaerobicbacteria attacking the vessel. By eliminating residue and sticky tackyproperties, the adhesion of bacteria slime colonies that typicallyaccelerate anaerobic bio-film corrosion is eliminated, or at leastminimized. By adding only limited amounts of ozone, some of the bacteriabut not all (in the stripper reactor) may be killed. In a preferredembodiment, the feed to the stripper reactor is heated to temperatureshigh enough to pasteurize the scrubber reactor liquid whilesimultaneously flashing the VCs into the gas phase which has its ownbenefits described above. As the detackification process createssurfactants that in turn makes an environment where the bacteria cannotreadily adhere to the wash section surfaces to form colonies,substantial killing (or sterilization) of the bacteria becomesunnecessary, just limiting the growth is sufficient to extend the lifeof the vessel. This also creates an oxygenated environment that furtherlimits the future growth of anaerobic bacteria. Thus, bio-corrosioncaused by anaerobic bacteria is avoided, or at least minimized, withoutthe use of additional toxic biocides.

Likewise, filtration is positively affected as a result ofdetackification. Without detackification, the waste solids would bevirtually glued to any filter used to separate liquid from solid,creating inefficiencies and leaving a liquefied, hazardous waste sludge.By conversion in the current process, these hazardous wastes areconverted to non-hazardous wastes or even by-products that can then beshipped to recyclers without the cost and difficulty incurred inshipping hazardous waste and locating recyclers qualified to handlehazardous waste. The present invention is also useful to those recyclerswho receive hazardous waste as they can convert such waste tonon-hazardous waste by using the method of the current invention.

One problem identified with oxygenation of long chain hydrocarboncontaminants and continuous recycling includes the accumulation ofsoaps. While the presence of soap is desirable for increasing thecapacity of the cleaning or scrubbing solution, metal ions tend toconvert carboxylates, the intermediate products, into metal salts (i.e.,metal carboxylates) that may be insoluble and could eventually producescale if not periodically removed. Scale, in turn, lowers the efficiencyof heat transfer equipment and creates other process problems. Scaletypically consists of carbonate scale. Insoluble carbonates are leftbehind, particularly as water is boiled off, leaving deposits. Thedeposit is a poor conductor of heat and the efficiency of a heatexchanger is thereby decreased. Therefore, in a preferred embodiment ofthis invention, recycled liquids are slowly bled to secondary treatmentsuch as a bioreactor or discharged to a POTW or local waste watertreatment system, such that the final products are water and biosludgethat can possibly be re-used as fertilizer or the like. Application ofthe present invention reduces the formation of scale as non-ionicsurfactants, chelating agent surfactants and sequestering agentsurfactants are created through the partial reaction of thecontaminants. These substances do not form a precipitate when combinedwith calcium, iron or the like. In this fashion, scaling is avoided, orat least minimized, in the stripper reactor, scrubber reactor and heatexchanger.

While the present invention addresses the problem of chemicallyconverting contaminants from excess paint involved in paintingoperations, the present invention can also be applied to left overunused waste paint. Disposal of excess paint, even in its originalcontainer, is a hazardous waste problem Similarly, paint sludge is anindustry problem. Just as the ozone applied in the reactor of thepresent invention converts the paint present in solution, the stripperoxygenation reactor can be used to convert and treat paint sludge andexcess paint. Disposal of paint is a particularly large problem forpaint shops and maintenance sheds. Preferably, the paint is dilutedbefore introduction to the reactor. Again, the process can becontinuous, batch or continuous batch with recovery of valuable productspossible or with the disposal of the intermediate products to differentapplications such as a bioreactor that produces fertilizer. In thismanner, a hazardous waste becomes a useful product.

The difference in amounts of oxygenation reagent required as opposed tototal oxidation can be 10 to 1000 orders of magnitude in difference.Also, by concentrating the contaminants into a smaller volume and/or bytreating a slip-stream in a continuous batch mode, the size of thereaction vessel, whether scrubber or reactor, is minimized. Ozonegenerators come in a variety of types and can be prohibitivelyexpensive. By reducing the ozone requirement by 10 to 1000 orders ofmagnitude as compared to total destruction, it is now possible toregenerate solution from a paint shop, for example, with a simpleV-generator at a fraction of the cost necessary for total destruction.Vessel costs will also be reduced dramatically. As shown above,reduction of scale and deposit on vessels results in decrease ofoperating costs, as does detackification of paint. Thus, the result ofapplication of the present invention is a surprising reduction of costassociated with effective treatment of the contaminants.

A preferred embodiment of reacting contaminants with the oxygenationreagent includes controlling pH in the reaction zone between 9 and 11using sodium or potassium hydroxide, sodium or potassium carbonate, orthe like as the preferred alkali. By maintaining the solution at this pHthroughout the process, the anaerobic biocide effect (and thereforecorrosion control) is further enhanced without addition of highly toxicbiocides.

While several embodiments have been described and illustrated, it willbe understood that the invention is not limited thereto since manymodifications may be made and equivalent structures will become apparentto those skilled in the art to which the invention pertains.

1. A method of treating a contaminated fluid having at least onecontaminant which is tacky, the method comprising: contacting thecontaminated fluid with an effective amount of an agent selected fromoxidizing agents, free radical producing agents and a combinationthereof for an effective amount of time to convert a substantial amountof the at least one contaminant to at least one corresponding modifiedcontaminant which is non-tacky; and generating a treated fluid having alevel of the at least one contaminant and of the at least onecorresponding modified contaminant to allow the treated fluid to atleast meet requirements for release, reuse or further treatment.
 2. Amethod of treating a contaminated fluid having at least one contaminanthaving a property selected from the group consisting of being volatile,hazardous, tacky and a combination thereof, the method comprising:contacting a contaminated off-gas containing the at least onecontaminant with a contacting liquid to remove at least a substantialportion of the at least one contaminant from the contaminated off-gasgenerating a treated off-gas and the contaminated fluid; contacting thecontaminated fluid with an effective amount of an agent selected fromoxidizing agents, free radical producing agents and a combinationthereof for an effective amount of time to convert a substantial amountof the at least one contaminant to at least one corresponding modifiedcontaminant having a property selected from the group consisting ofbeing non-volatile, less volatile than the contaminant, non-hazardous,less hazardous than the contaminant, non-tacky and a combinationthereof; generating a treated fluid having a level of the at least onecontaminant and of the at least one corresponding modified contaminantto allow the treated fluid to at least meet requirements for release,reuse or further treatment; and cooling the contaminated off-gas priorto contacting with the contacting liquid to at least partially condensea portion of the at least one contaminant to facilitate removal thereofby the contacting liquid.
 3. A method of treating a contaminated fluidhaving at least one contaminant having a property selected from thegroup consisting of being volatile, hazardous, tacky and a combinationthereof, the method comprising; contacting a contaminated off-gascontaining the at least one contaminant with a contacting liquid toremove at least a substantial portion of the at least one contaminantfrom the contaminated off-gas generating a treated off-gas and thecontaminated fluid; contacting the contaminated fluid with an effectiveamount of an agent selected from oxidizing agents, free radicalproducing agents and a combination thereof for an effective amount oftime to convert a substantial amount of the at least one contaminant toa least one corresponding modified contaminant having a propertyselected from the group consisting of being non-volatile, less volatilethan the contaminant, non-hazardous, less hazardous than thecontaminant, non-tacky and a combination thereof; generating a treatedfluid having a level of the at least one contaminant and of the at leastone corresponding modified contaminant to allow the treated fluid to atleast meet requirements for release, reuse or further treatment; andcooling the contaminated off-gas by contacting with the contactingliquid that is cooler than the contaminated off-gas to at leastpartially condense a portion of the at least one contaminant tofacilitate removal thereof by the contacting liquid.
 4. A method oftreating a contaminated off-gas having at least one contaminant having aproperty selected from the group consisting of being volatile,hazardous, tacky and a combination thereof, the method comprising:contacting the contaminated off-gas with a contacting liquid and anagent having ozone; partially oxidizing a portion of the at least onecontaminant with the ozone to at least one corresponding modifiedcontaminant having increased water solubility, thereby increasing thecontaminant carrying capacity of the contacting liquid; and generating atreated fluid baying a level of the at least one contaminant and of theat least one corresponding modified contaminant to allow the treatedfluid to at least meet requirements for release, reuse or furthertreatment, wherein the at least one corresponding modified contaminanthas a property selected from the group consisting of being non-volatile,less volatile than the contaminant, non-hazardous, less hazardous thanthe contaminant, non-tacky and a combination thereof.
 5. The method ofclaim 4, wherein the contaminated off-gas is selected from the groupconsisting of off-gases from paint shops, bakeries, restaurants, drycleaners and burning of fossil fuel.
 6. The method of claim 4, whereinthe contaminated off-gas is selected from the group consisting ofoff-gases from industrial processes, pharmaceutical processes, solventcleaning processes, solvent degreasing processes, fiberglass operations,ink and printing operation, wood and wood products drying processes,food industries, rinsing processes and paper mills.
 7. The method ofclaim 4, further comprising: recycling at least a portion of the treatedliquid to the contacting liquid.
 8. The method of claim 4, wherein thecontaminated off-gas and the contacting liquid are contactedcounter-currently or co-currently.
 9. The method of claim 4, furthercomprising: feeding at least a portion of the treated fluid to abioreactor for bioconversion.
 10. A method of treating a contaminatedfluid having at least one contaminant having a property selected fromthe group consisting of being volatile, hazardous, tacky and acombination thereof, the method comprising: contacting a contaminatedoff-gas containing the at least one contaminant with a contacting liquidto remove at lean a substantial portion of the at least one contaminantfrom the contaminated off-gas generating a treated off-gas and thecontaminated fluid; contacting the contaminated fluid with an effectiveamount of an agent selected from oxidizing agents, free radicalproducing agents and a combination thereof for an effective amount oftime to convert a substantial amount of the at least one contaminant toat least one corresponding modified contaminant having a propertyselected from the group consisting of being non-volatile, less volatilethan the contaminant, non-hazardous, less hazardous than thecontaminant, non-tacky and a combination thereof; generating a treatedfluid having a level of the at least one contaminant and of the at leastone corresponding modified contaminant to allow the treated fluid to atleast meet requirements for release, reuse or further treatment, whereinthe treated fluid is a treated liquid; and filtering the treated liquidto generate a filtered liquid and collected materials.
 11. The method ofclaim 10, further comprising: recycling at least a portion of thefiltered liquid to the contacting fluid.
 12. A method of treating acontaminated fluid having at least one contaminant having a propertyselected from the group consisting of being volatile, hazardous, tackyand a combination thereof, the method comprising: stripping volatilecontaminants from a contaminated liquid stream by contacting thecontaminated liquid stream with a stripping stream to generate a treatedliquid stream and a contaminated off-gas; contacting the contaminatedoff-gas containing the at least one contaminant with a contacting liquidto remove at least a substantial portion of the at least one contaminantfrom the contaminated off-gas generating a treated off-gas and thecontaminated fluid; contacting the contaminated fluid with an effectiveamount of an agent selected from oxidizing agents, free radicalproducing agents and a combination thereof for an effective amount oftime to convert a substantial amount of the at least one contaminant toat least one corresponding modified contaminant having a propertyselected from the group consisting of being non-volatile, less volatilethan the contaminant non-hazardous, less hazardous than the contaminant,non-tacky and a combination thereof; and generating a treated fluidhaving a level of the at least one contaminant and of the at least onecorresponding modified contaminant to allow the treated fluid to atleast meet requirements for release, reuse or further treatment.
 13. Themethod of claim 12, wherein the treated liquid stream is the contactingliquid.
 14. The method of claim 13, wherein the method is performed in asingle vessel with the contaminated fluid and contaminated off-gas beinginternal to the vessel.
 15. The method of claim 14, wherein thecontaminated liquid stream is fed at or near the top of the vessel andthe shipping stream is fed at or near the bottom of the vessel.
 16. Themethod of claim 15, wherein the agent is fed at a point between the topand bottom of the vessel.
 17. The method of claim 13, wherein thestripper stream is or contains the agent.
 18. The method of claim 13,wherein the treated liquid is fed to a bioreactor.
 19. The method ofclaim 18, wherein the treated off-gas is fed to the bioreactor.
 20. Themethod of claim 19, wherein the treated off-gas has an oxygenconcentration greater than ambient air.
 21. The method of claim 12,wherein the stripping stream is selected from the group consisting ofair, steam and a mixture thereof.
 22. A method of treating acontaminated fluid having at least one contaminant having a propertyselected from the group consisting of being volatile, hazardous, tackyand a combination thereof, the method comprising: contacting thecontaminated fluid with an effective amount of an agent selected fromoxidizing agents, free radical producing agents and a combinationthereof for an effective amount of time to convert a substantial amountof the at least one contaminant to at least one corresponding modifiedcontaminant having a property selected from the group consisting ofbeing non-volatile, less volatile than the contaminant, non-hazardous,less hazardous than the contaminant, non-tacky and a combinationthereof; generating a treated fluid having a level of the at least onecontaminant and of the at least one corresponding modified contaminantto allow the treated fluid to at least meet requirements for release,reuse or further treatment; filtering the treated fluid to generate afiltered fluid and collected materials; and feeding the filtered fluidto a bioreactor for bioconversion.
 23. A method of treating acontaminated fluid having at least one contaminant having a propertyselected from the group consisting of being volatile, hazardous, tackyand a combination thereof, the method comprising: contacting thecontaminated fluid with an effective amount of an agent selected fromoxidizing agents, free radical producing agents and a combinationthereof for an effective amount of time to convert a substantial amountof the at least one contaminant to at least one corresponding modifiedcontaminant having a property selected from the group consisting ofbeing non-volatile, less volatile than the contaminants non-hazardous,less hazardous than the contaminant, non-tacky and a combinationthereof; and generating a treated fluid having a level of the at leastone contaminant and of the at least one corresponding modifiedcontaminant to allow the treated fluid to at least meet requirements forrelease, reuse or further treatment, wherein the contaminated fluid iswater that contains paint which also contains a floating contaminant andthe method further comprising removing the floating contaminant prior tocontact with the agent to generate a skimmed water stream and skimmedcontaminant.
 24. A method of treating a contaminated fluid having atleast one contaminant having a property selected from the groupconsisting of being volatile, hazardous, tacky and a combinationthereof, the method comprising: contacting the contaminated fluid withan effective amount of an agent selected from oxidizing agents, freeradical producing agents and a combination thereof for an effectiveamount of time to convert a substantial amount of the at least onecontaminant to at least one corresponding modified contaminant having aproperty selected from the group consisting of being non-volatile, lessvolatile than the contaminant, non-hazardous, less hazardous than thecontaminant, non-tacky and a combination thereof; and generating atreated fluid having a level of the at least one contaminant and of theat least one corresponding modified contaminant to allow the treatedfluid to at least meet requirements for release, reuse or furthertreatment, wherein the contaminated fluid is water that contains paintand wherein the agent has the additional property of detackifying tackycomponents in paint and the agent is added in an effective amount toalso detackify such tacky components.
 25. The method of claim 24,further comprising: filtering the treated fluid to generate a filteredfluid and a recovered material.
 26. The method of claim 25, wherein therecovered material is separated to recover desired materials selectedfrom the group consisting of pigments, monomers, metals and combinationsthereof.
 27. The method of claim 24, wherein the water that containspaint is wash water from a paint booth.
 28. The method of claim 24,wherein the water that contains paint is obtained by combining waterwith paint that requires disposal.
 29. The method of claim 24, whereinthe water that contains paint is paint sludge.
 30. In a main processthat utilizes a contacting gas and generates at least one main off-gascontaining at least one contaminant, a treating process comprising:contacting a contaminated off-gas containing the at least onecontaminant with a contacting liquid to remove at least a substantialportion of the at least one contaminant from the contaminated off-gasgenerating a treated off-gas and a contaminated fluid; contacting thecontaminated fluid with an effective amount of an agent selected fromoxidizing agents, free radical producing agents and a combinationthereof for an effective amount of time to convert a substantial amountof the at least one contaminant to at least one corresponding modifiedcontaminant having a property selected from the group consisting ofbeing non-volatile, less volatile than the contaminant, non-hazardous,less hazardous than the contaminant, non-tacky and a combinationthereof; and generating a treated fluid having a level of the at leastone contaminant and of the at least one corresponding modifiedcontaminant to allow the treated fluid to at least meet requirements forrelease, reuse or further treatment, wherein the at least one mainoff-gas is the contaminated off-gas, wherein the at least onecontaminant has a property selected from the group consisting or beingvolatile, hazardous, tacky and a combination thereof, and wherein atleast a portion of the treated off-gas is recycled to the contactinggas.
 31. The process according to claim 30, wherein the at least onemain off-gas is a plurality of main off-gas streams and wherein theplurality of main off-gas streams are combined to form the contaminatedoff-gas.
 32. A method of treating a contaminated liquid having at leastone contaminant having a property selected from the group consisting ofbeing volatile, hazardous, tacky and a combination thereof, the methodcomprising: contacting the contaminated liquid with an effective amountof an agent having ozone; partially oxidizing a portion of the at leastone contaminant with the ozone to at least one corresponding modifiedcontaminant having increased water salability, thereby increasing thecontaminant carrying capacity of the contaminated liquid; generating atreated fluid having a level of the at least one contaminant and of theat least one corresponding modified contaminant to allow the treatedfluid to at least meet requirements for reuse as a metal finishingphosphating bath liquid, wherein the contaminated fluid liquid is acontaminated metal finishing phosphating bath liquid, wherein the ozoneis added in an effective amount to also act as a phosphate-coatingaccelerator, a secondary phosphate-coating accelerator compoundproducer, phosphate-coating accelerator compound regenerator orcombination thereof therein or as the phosphate coating accelerator, andwherein the at least one corresponding modified contaminant havingincreased water solubility increases the contaminant carrying capacityof the treated fluid.